Merge pull request #2861 from minrk/missing_km

add missing KernelManager to ConsoleApp class list

closes #2860
split base_launch_kernel into make_kernel_cmd / launch_kernel
remove obsolete launch_kernel in ipkernel
allow custom kernel_cmd in KernelManager
allow KM._launch_kernel to be overridden in subclasses
s/make_kernel_cmd/make_ipkernel_cmd/
move IPython.lib.kernel to IPython.utils.kernel

where it always should have been.
move IPython.zmq.entry_point to IPython.utils.kernel